Microtubules are hollow polymers made up of tubulin subunits. Neurons, like other eukaryotic cells, contain a pool of free tubulin subunits and a pool of the microtubule polymers. These two pools dynamically exchange with one another such that microtubules undergo bouts of assembly and disassembly.n neurons, microtubules are also nucleated at the centrosome (located in the cell body of the neuron), but the microtubules are then severed from the centrosome so that they can be deployed into axons and dendrites.
If the parent makes this election, the child does not have to file a return. Earned and Unearned Income. If a child has both earned and unearned income, he or she must file a return (2016 and 2015) if: unearned income was over $1,050; earned income was over $6,300, or
Single dependents also are required to file tax returns if their gross income is more than the larger of $950 or their earned income (up to $5,400) plus $300. Married dependents are required to file a tax return if their unearned income is over $2,050 or their earned income is over $6,800.Married dependents also are required to file tax returns if their gross income is more than the larger of $2,050 or their earned income (up to $5,400) plus $1,400.or example, rules regarding contributions to a Roth IRA are tied to your amount of earned income, and taxpayers who don't have any earned income aren't allowed to claim the earned income tax credit (EITC).